Its a matter of practice to figure out how big a flake (or part of) a tad will eat. After working at petsmart I tested a number of fish flakes on tads, the wide variety of fish flakes available are great for tailoring to specific tad needs (some are more veggie lovers, some like more protien like thumbs). There are flakes made mostly of sprulina and the like (compare brands, a lot have fillers so it might be better to make your own) and also some more for mosquito larvae lovers (like livebearer food).
One of the things I don't like about the tadpole pellets is that they are pellets... if a tad only eats part of a flake and a pellet is like a couple flakes condensed its more food than the smaller tads will eat in a sitting. It may work for larger tads if the recognize it as food. The brand is also not one that I'm fond of, so I wouldn't use it for that reason too, when I have better quality fish flakes (some are also in pellet form) from companies I like better.